Study type: Medical/biological study (experimental study)

Rodent cell transformation and immediate early gene expression following 60-Hz magnetic field exposure. med./bio.

Published in: Environ Health Perspect 1996; 104 (11): 1188-1198

Aim of study (acc. to author)

To investigate the in vitro effects of 60 Hz magnetic fields on gene expression that can result in neoplastic transformation in different cell lines.

Background/further details

Cell transformation was examined in C3H 10T1/2 murine fibroblasts and Syrian hamster embryo (SHE) cells.
To determine c-myc, c-fos, ß-actin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene expression HL-60 cells were used. Ornithine decarboxylase gene expression was studied in C3H 10T1/2 cells.
1.5 Gy gamma rays radiation was used as a positive transformation response in SHE or C3H 10T1/2 cells.
The positive controls in the gene expression of c-myc and c-fos in HL-60 cells and the gene expression of ornithine decarboxylase in C3H 10T1/2 cells were hyperthermia (45.5°C) and TPA treated cells.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: continuous for 10 , 20 and 40 min
Exposure 2: 60 Hz
Exposure duration: continuous for 24 h

General information

1.5 Gy of X-ray was used to elicit a positive transformation response in SHE or CH3/10T1/2 cells and as negative control for c-fos expression in HL60 cells. Hyperthermia at 45.5°C for 9 min and TPA at 0.3 µg/ml for 30 min or 50 ng/ml for 3 h were used as treatments modifying the expression of c-myc, c-fos and ODC.

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Exposure duration continuous for 10 , 20 and 40 min
Additional info HL60 cells were exposed. Reference Article: Little JB, Nagasawa H, Kennedy AR. DNA repair and malignant transformation : effect of X radiation , 12-O-tetradecanoyl-phorbol-13-acetate, and protease inhibitors on transformation and sister-chromatid exchanges in mause 10 T1/2 cells.
Exposure setup
Exposure source
Chamber water bath insulated with styrofoam ( 1.2 m long, 0.7 m wide, 11 cm deep) maintained at 37°C.
Setup solenoids, 38.7 cm long, 12 cm in diameter, 199 turns; tissue culture flasks were placed horizontally in the central planes of long solenoids wound on thin-walled plexiglas cylinders enclosed in magnetic shield cylinders (22.9 cm in diameter), all of them were placed parallel to each other in water bath; cells were parallel to the field lines which was uniform along the 18 cm long central plane.
Sham exposure A sham exposure was conducted.
Additional info Control cells experienced zero magnetic field but were subjected to the same level of disturbance such as local acoustic noise and convective heating.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 5.7 µT minimum measured unspecified -
magnetic flux density 57 µT - - - -
magnetic flux density 570 µT maximum - - -

Exposure 2

Main characteristics
Frequency 60 Hz
Type
Exposure duration continuous for 24 h
Additional info C3H/10T1/2 cells and SHE cells were exposed
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 200 µT unspecified measured unspecified -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

No transformed colonies were found in SHE cells exposed to 60 Hz magnetic fields.
There were no significant differences in plating efficiency among exposed and sham exposed C3H 10T1/2 cells. Incubation in TPA enhanced the transformation induced by 1.5 Gy gamma rays radiation. TPA incubation in exposed and sham exposed cells alone had no effect.
Exposure to 60 Hz magnetic fields had no effect on ornithine decarboxylase gene expression whereas treatment with TPA increased ornithine decarboxylase transcription level in exposed and sham exposed SHE cells.
No statistically significant effects were observed in gene expression in HL-60 cells exposed to 60 Hz magnetic fields.

Study character:

Study funded by

Related articles